1. The Field of the Invention
This invention relates to transcutaneous access, and, more particularly, to methods and apparatus for use in establishing and maintaining stable transcutaneous access.
2. The Relevant Technology
Many medical situations require the establishment of transcutaneous access into a region of a patient's body. Transcutaneous access has been long practiced for numerous medical treatments, and the establishment of stable transcutaneous access has long been the subject of discussion and clinical investigations and treatment. Unfortunately, serious problems frequently occur when attempting to achieve transcutaneous access. Both for short term and chronic access, infection of the access site often results in failure of the device placement. The modes of failure vary from local exit site infections to deeper pocket infections or even more remote infections with continuation of the infection to involve areas distant from the transcutaneous exit site. An example of such implant device failures is exemplified by continuous ambulatory peritoneal dialysis (CAPD) catheters. Many innovations have been instituted to try to eliminate the infections associated with these transcutaneous catheters.
These infections fall into several general categories, although it will be appreciated that these problems are interrelated, and may also be thought of as lying along a continuum. One common problem is manifested as an exit site infection, which involves an infection from the location where the catheter enters the skin to, generally speaking, the location of the first Dacron subcutaneous cuff. This is an area typically from 1.0 cm to 2.5 cm from the surface of the skin where the catheter exits the skin. The next is a tunnel infection, which is an infection involving the first Dacron cuff and along the tunnel of the subcutaneous course of the catheter to or involving the second Dacron cuff, if one is supplied, which is generally located in the rectus abdominus muscle. Another type of infection is peritonitis, which involves the peritoneal space along with the catheter within the peritoneum. It is believed that an exit site infection can proceed to a tunnel infection and subsequently cause peritonitis, demonstrating the interrelationships of these infections. Many efforts have been directed toward reducing the incidence of exit site infection, but little change in exit site infection rates has been observed, despite new advances in cuffing materials, implant techniques and exit site care.
Another example of failure of transcutaneous access has been observed in connection with artificial heart and heart assist lines, where either a transcutaneous access is needed for electrical power and possibly venting, or pneumatic powering of the heart. Here the infection(s) may involve the exit site, proceed along the drive line to the pump pocket where it can involve the entire pocket of the pump and subsequently to the vascular grafts. Even though it is rare for these infections to cause the demise of the patient, they do create significant morbidity and expense associated with treatment, and may require operative intervention.